[BUG] Auto-compact is broken — feature is effectively useless

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Auto-compact is broken. The feature used to work reliably — it would trigger when context got large and keep sessions manageable. Now it either doesn't trigger when it should, triggers at the wrong time, or fails to actually reduce context meaningfully. The feature has become effectively useless compared to how it worked before.

What Should Happen?

Auto-compact should trigger appropriately when context approaches the limit and actually reduce the conversation context, keeping sessions functional without manual intervention.

Error Messages/Logs

No explicit errors — the feature just doesn't work as expected.

Steps to Reproduce

1. Start a Claude Code session
2. Work through a long session until context grows large
3. Observe that auto-compact either fails to trigger, or doesn't meaningfully compact the conversation

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — noticed the degradation over time

Claude Code Version

2.1.42

Platform

Anthropic API

Operating System

Linux (6.18.9-2-cachyos)

Terminal/Shell

zsh

Additional Information

_No response_